https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101174
Bug ID: 101174
Summary: [12 Regression] CTAD causes instantiation of invalid
specialization
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ppalka at gcc dot gnu.org
Target Milestone: ---
The following testcase
struct S { using type = int; };
template<class T = int, class U = S>
struct multiset {
using type = typename U::type;
multiset(T);
multiset(U);
};
template<class T>
multiset(T) -> multiset<T>;
multiset c(42);
is rejected by GCC 12 with
<stdin>: In instantiation of ‘struct multiset<int, int>’:
<stdin>:13:14: required from here
<stdin>:5:9: error: ‘int’ is not a class, struct, or union type
<stdin>:7:3: error: ‘multiset<T, U>::multiset(U) [with T = int; U = int]’
cannot be overloaded with ‘multiset<T, U>::multiset(T) [with T = int; U = int]’
<stdin>:6:3: note: previous declaration ‘multiset<T, U>::multiset(T) [with T =
int; U = int]’
